CellRendererIcon: add active state - SL #3989

For press feedback.  Do this connecting to the treeview press and
release signals, as the palette invoker does.  After this, the active
state can be styled in the artwork.

Signed-off-by: Manuel Quiñones <manuq@laptop.org>
Acked-by: Simon Schampijer <simon@laptop.org>

src/sugar3/graphics/icon.py

@@ -758,15 +758,28 @@ class CellRendererIcon(Gtk.CellRenderer):
         self._stroke_color = None
         self._prelit_fill_color = None
         self._prelit_stroke_color = None
+        self._active_state = False
         self._palette_invoker = CellRendererInvoker()
 
         Gtk.CellRenderer.__init__(self)
 
+        tree_view.connect('button-press-event',
+                          self.__button_press_event_cb)
+        tree_view.connect('button-release-event',
+                          self.__button_release_event_cb)
+
         self._palette_invoker.attach_cell_renderer(tree_view, self)
 
     def __del__(self):
         self._palette_invoker.detach()
 
+    def __button_press_event_cb(self, widget, event):
+        if self._point_in_cell_renderer(widget, event.x, event.y):
+            self._active_state = True
+
+    def __button_release_event_cb(self, widget, event):
+        self._active_state = False
+
     def create_palette(self):
         return None
 
@@ -863,14 +876,21 @@ class CellRendererIcon(Gtk.CellRenderer):
                          flags):
         pass
 
-    def _is_prelit(self, tree_view):
-        x, y = tree_view.get_pointer()
-        x, y = tree_view.convert_widget_to_bin_window_coords(x, y)
-        pos = tree_view.get_path_at_pos(x, y)
+    def _point_in_cell_renderer(self, tree_view, x=None, y=None):
+        """Check if the point with coordinates x, y is inside this icon.
+
+        If the x, y coordinates are not given, they are taken from the
+        pointer current position.
+
+        """
+        if x is None and y is None:
+            x, y = tree_view.get_pointer()
+            x, y = tree_view.convert_widget_to_bin_window_coords(x, y)
+        pos = tree_view.get_path_at_pos(int(x), int(y))
         if pos is None:
             return False
 
-        path_, column, x, y = pos
+        path_, column, x, y_ = pos
 
         for cell_renderer in column.get_cells():
             if cell_renderer == self:
@@ -886,13 +906,19 @@ class CellRendererIcon(Gtk.CellRenderer):
         context.save()
         context.add_class("sugar-icon-cell")
 
+        pointer_inside = self._point_in_cell_renderer(widget)
+
         # The context will have prelight state if the mouse pointer is
         # in the entire row, but we want that state if the pointer is
         # in this cell only:
         if flags & Gtk.CellRendererState.PRELIT:
-            if not self._is_prelit(widget):
+            if pointer_inside:
+                if self._active_state:
+                    context.set_state(Gtk.StateFlags.ACTIVE)
+            else:
                 context.set_state(Gtk.StateFlags.NORMAL)
 
+
         Gtk.render_background(context, cr, background_area.x, background_area.y,
                               background_area.width, background_area.height)
 
@@ -914,7 +940,7 @@ class CellRendererIcon(Gtk.CellRenderer):
                                          prelit_stroke_color]
 
         if flags & Gtk.CellRendererState.PRELIT and has_prelit_colors and \
-                self._is_prelit(widget):
+                pointer_inside:
 
             self._buffer.fill_color = prelit_fill_color
             self._buffer.stroke_color = prelit_stroke_color